Effects of cations on the sugar receptor-site of the blowfly, Phormia

1 December 1978

journal article
research article
Published by Oxford University Press (OUP) in Chemical Senses

Vol. 3 (4) , 413-422
https://doi.org/10.1093/chemse/3.4.413

Abstract

1) Ca^{+ +} (1 to 10 mM) lowered the binding affinity of sugar receptor-site for sucrose in the labellar sugar receptor of the blowfly, Phormia regina, without changing the maximum-response amplitude. It also elevated the values of the Hill coefficient (n_H) in some degrees. 2) Other divalent cations such as Mg^{+ +}, Ba^{+ +} or Cd^{+ +} also showed almost the same property as above. The sequence of the effect is as follows: Ba^{+ +}, Mg^{+ +} × Ca^{+ +} × Cd^{+ +}. Trivalent cation, La^{+ + +} (1 mM), changed the value of n_H from 1 (La^{+ + +}-free) to 2. 3) On the contrary, the action of monovalent cations such as K⁺ or Na⁺, of which ionic strength was made the same as that of the divalents hardly suppressed the response. 4) The results obtained do not support the hypothesis, at least on the sugar receptor of the fly, that the receptor potential is attributable to a change of the surface potential (zeta potential) as is proposed for the frog sugar receptor.

Keywords

This publication has 0 references indexed in Scilit: